Fleet Overview

CSL Australia operates a highly specialized fleet of self-unloading vessels that handle a range of cargoes within coastal trades of Australia. For information on the functionality of each vessel type, simply click on the links below.

Scraper-Reclaimer Self-Unloaders

Pneumatic Self-Discharging Cement Carrier
Gravity Self-Unloader
Hybrid Self-Unloading Bulk Carrier

Scraper-Reclaimer Self Unloader

Scraper-reclaimer vessels are utilized on the Australian coast due to the mix of powdered and granular cargoes carried for the construction industry. While a gravity self-unloader can discharge at a higher rate, it will be restricted to free-flowing granular cargoes and cannot carry cargoes that flow too readily such as cement and fly-ash. Scraper-reclaimer vessels can handle granular materials such as gypsum plus powder materials such as cement and fly-ash. Further, these vessels are not as dependent on free-flowing cargoes and handle more cohesive (stickier) materials. The potential discharge rates are lower, but takeaway rates for the construction industry are 2,000 t/hr at the top end. Many receiving facilities are limited to rates below 1,000 t/hr. CSL’s vessels, the CSL Pacific, the Stadacona and the CSL Thevenard are scraper reclaimer vessels. The description below applies to the CSL Thevenard and the CSL Pacific. The Stadacona operates in a similar fashion.

The unloading system consists of a hoistable scraper system in the holds, elevators, conveyors on deck and a boom conveyor. The scrapers, in all positions, are located above the cargo level. The transverse scraper moves the cargo towards the longitudinal scraper, which transfers it to the bucket elevator. The transverse scraper is supported by two rails, one longitudinal rail is attached to a longitudinal beam on one side and one rail is attached to the longitudinal scraper on the other side. The transverse scraper moves longitudinally on the rails by using a specially-designed traversing drive unit. The longitudinal beam and the longitudinal scraper slide vertically in guides fitted to the ship’s structure and can be hoisted and lowered by a winch through a system of wires. Bucket elevators lift the cargo above deck level to the conveyor system on deck. The deck conveyor transports the cargo to the discharge boom that moves cargo to the unloading point ashore.

Dust and noise control
Cargo loading and discharging can be carried out within a completely enclosed system. This ensures a clean ship and a clean dock, no dust pollution around the harbour and reduced noise levels. This enclosed system protects cargo from rain and wind. Dust collectors are used to minimize dust leakage from the conveying system. The dust collectors take air from critical points to create negative pressure inside the conveyors.

Dusty cargoes such as cement powder are loaded through sealed ports in the hatch covers for completely closed loading.

Noise generated by the ship’s self unloading machinery is controlled through the use of acoustic enclosures and sound barriers.

Pneumatic Self-Discharging Cement Carrier

The Goliath is a pneumatic self discharging cement carrier built specifically to handle powder cargoes such as cement. The Goliath loads and discharges using lean-phase pneumatic conveying systems. The cargo holds have sloping bottom surfaces fitted with air slides. The cement powder is fluidized when compressed air is injected into the air slides below the cargo, and the sloping surfaces of the cargo hold move the cement toward the center tunnel for discharging. Rotary valves and cement screws in the tunnel inject the cement into the discharge piping where high volumes of transport air entrain the cement and carry it in suspension through the discharge pipelines to a storage silo ashore

The same pipelines are used to load the vessel through a single point. Distribution pipes on the vessel direct the cement powder into the hold to be loaded, and large dust collectors are used to evacuate the transport air from the holds and filter out the dust.

Pneumatic conveying is very energy intensive, and the Goliath’s electrical generators are augmented by a high-voltage shore power system to power the transport air compressors. The Goliath, in turn, supplies transport air to the system ashore for loading.

The pneumatic conveying technology on the ship is matched with the system on shore to account for pipeline restrictions and high volumes of air. This ensures optimum loading and discharging rates — typically 1,000 t/hr.

Loading and unloading is completely enclosed, and this type of vessel is expected to operate completely dust-free.

Gravity Self-Unloader

Gravity self-unloaders with hoppered holds and gravity gates are the mainstay of CSL operations around the world. These vessels are suitable for granular free-flowing cargoes. CSL Australia also operates a vessel of this type, the Iron Chieftain.. This vessel is equipped with two tunnels, Stephenson Adams Bulk Flow gates, a loop belt elevating system and discharge boom aft. This system permits relatively high discharge rates. The Iron Chieftain operates between steel plants on the Australian coast carrying iron ore and coal.

Hybrid Self-Unloading Bulk Carrier

The CSL Atlantic is a hybrid self-unloading bulk carrier. The vessel was initially built with marine cranes serving each of the four holds for self-loading and self-discharging. To improve the discharging and provide a clean single-point discharge, the vessel underwent a ‘hybrid’ conversion. This meant the installation of shipboard hoppers, conveying systems and a discharge boom, as well as additional electrical generators to power the new equipment. With these features, the cranes grab from the cargo holds and discharge into a hopper adjacent to each hold. This reduces the cycle-time for the cranes and increases the overall discharge rate

These vessels are suitable for granular free-flowing cargoes. From the deck conveyors onward, a hybrid self-unloader operates in the same fashion as a gravity self unloader. The cargo is conveyed out of the hoppers along the deck to cross conveyors or elevating systems that move the cargo onto the boom for discharging ashore. Location of the boom drives the complexity of transfers and elevating systems. In the case of the CSL Atlantic, the discharge boom is mounted amidships on the port side, so the transfer and elevation of cargo to the boom can be accomplished using only a cleated inclined conveyor

Pay loaders are used for cleanup of material in the holds that cannot be removed by the grabs.